I use this clear film https://www.invisiblepatterns.co.uk/bikes/norton-cafe-racer-2011. It doesn't cover the whole tank, just the areas that you would rub with your knees and pants/zipper. I had to light it up so you can see the outline in the photo but in normal daylight it barely shows. I'm 5'10" and I find the Thruxton R riding position is ok for me but after a couple of years I had to admit defeat with the 961 Cafe Racer and change the clip-ons for the normal bars. For me it was age and knackered joints (mine). So if the low riding position does become a pain, you've always got the option of the standard bars.